JP2011259308A - Image processing apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus which, when merging a mask image into an original image and then merging a stamp image into a mask image area of the original image, does not cause blurred colors or voids to occur on the fringe of the stamp image.SOLUTION: RGB data of an original image or a stamp image in PDL data format is input from an external personal computer 2 or RGB data is generated from an original image by reading the original image. Then the RGB data of the original image or the stamp image is subjected to irreversible compressing processing (e.g., JPEG compression processing), and the JPEG data is stored in a memory or the image data of mask image is generated based on the stamp image before being stored in the memory. Also, the JPEG data of the original image or the stamp image is read out from the memory and expanded to obtain their RGB data, and the RGB data of the original image or the stamp image is converted into CMYK data before the image data of mask image is read out from the memory, and then the mask image is merged into the original image.

Description

  The present invention relates to an image processing apparatus that superimposes and combines a stamp image on a document image, and an image forming apparatus including the image processing apparatus.

  2. Description of the Related Art Some image forming apparatuses such as multifunction peripherals have a function of combining a stamp image such as characters and codes with a document image and printing the document image obtained by combining the stamp image when the document image is printed. .

  However, in a color image, if the stamp image is simply combined with the document image, color mixing occurs between the stamp image and the document image, resulting in a decrease in image quality. Therefore, a mask image (white area) to be superimposed on the stamp image is generated, and this mask image is synthesized with the original image, and then the stamp image is superimposed on the mask image (white area) in the original image. In addition, color mixing is prevented.

  For example, in the system shown in FIG. 5, RGB data (image data) of a document image or a stamp image is transmitted and received in the form of PDL (page description language) data from the personal computer 101 to the image forming apparatus 102. In the image forming apparatus 102, PDL data is analyzed by the PDL data processing unit 103, RGB data of a document image or a stamp image is extracted, and these RGB data are irreversibly compressed by the JPEG compression processing unit 104. JPEG data (image data) of a document image or stamp image obtained by lossless compression is stored in the HDD 105.

  As for the stamp image, JPEG data is read from the HDD 105 and decompressed by the JPEG decompression processing unit 106 to generate RGB data of the stamp image, and the RGB data of the stamp image is processed by the mask generation processing unit 107 and masked. Image data of an image (binary image) is generated, the image data of the mask image is reversibly compressed by the JBIG compression processing unit 108, and the JBIG data (image data) of the mask image obtained by the lossless compression is stored in the HDD 105. Remember.

  Thereafter, when printing the original image, the JPEG data of the original image or the stamp image is read from the HDD 105 and decompressed and converted into RGB data, and the JBIG data of the mask image is also read from the HDD 105 and decompressed to obtain the mask image (2 Value image) image data. Then, after converting RGB data of the document image or stamp image into CMYK data suitable for printing by the image forming apparatus 102, the mask image (binary image) is synthesized with the document image, and the mask image (outlined image) in the document image is displayed. The stamp image is combined with this area), and the original image combined with this stamp image is printed.

  Patent Documents 1 and 2 disclose a technique in which an area of a character image (corresponding to a stamp image) is outlined with respect to an original image, and the character image is synthesized with the white area in the original image. ing.

Japanese Patent Laid-Open No. 5-16392 (published January 26, 1993) JP 2007-318468 A (released on December 6, 2007)

  However, as described above, when the image data of the stamp image is compressed and then expanded, the image quality of the stamp image is lowered, and the image quality of the mask image generated based on the stamp image is also lowered. For this reason, when the stamp image is combined with the mask image area in the document image, white spots appear on the periphery of the stamp image.

  In Patent Documents 1 and 2, there is no indication of such a problem, and no solution is described.

  Therefore, the present invention has been made in view of the above-described conventional problems. When a mask image is combined with a document image and then the stamp image is combined with the mask image area in the document image, the periphery of the stamp image is obtained. It is an object of the present invention to provide an image processing apparatus and an image forming apparatus in which whitening does not occur.

  In order to solve the above problems, an image processing apparatus of the present invention generates a mask image based on a stamp image, combines the mask image with a document image, and places the stamp image in a region of the mask image in the document image. An image processing apparatus for combining, a storage unit for storing the image data of the stamp image and the image data of the mask image, and generating the mask image based on the stamp image before being subjected to compression processing, and the mask A mask image generation unit that compresses image data of an image or stores the image data in the storage unit without compression.

  When the mask image is generated based on the stamp image before being subjected to compression processing in this way and the image data of the mask image is stored losslessly or without being compressed, the image quality of the mask image does not deteriorate. For this reason, even if the mask image is combined with the original image and the stamp image is combined with the mask image area in the original image, the peripheral edge of the stamp image is not whitened.

  In the image processing apparatus of the present invention, the image data of the mask image is read from the storage unit and processed without being expanded, and the mask image is combined with the document image, and is stored in the storage unit. The image processing apparatus includes a combining unit that reads out the image data of the stamp image and combines the stamp image with the mask image area in the document image.

  In this way, the mask image is combined with the original image, and the stamp image is combined with the mask image area in the original image.

  Furthermore, in the image processing apparatus of the present invention, the mask image generation unit compresses the image data of the stamp image and stores it in the storage unit. The synthesizing unit reads out the image data of the mask image from the storage unit and processes the decompressed image without decompression, and synthesizes the mask image with the document image, and the image data of the stamp image is The stamp image is combined with the area of the mask image in the original image by reading and decompressing from the storage unit.

  Even if irreversible compression is applied to the image data of the stamp image, the stamp image does not have a white edge, and the capacity of the image data of the stamp image can be reduced.

  In the image processing apparatus according to the aspect of the invention, the image data of the document image and the image data of the stamp image are RGB data, and the combining unit stores the image data of the document image and the image data of the stamp image. After converting from RGB data to CMYK data, the mask image is combined with the original image, and the stamp image is combined with the area of the mask image in the original image.

  On the other hand, an image forming apparatus of the present invention includes the image processing apparatus of the present invention.

  According to the present invention, when a mask image is generated based on a stamp image before being subjected to the reversible compression process and the image data of the mask image is stored in a reversible or uncompressed manner, Image quality does not deteriorate. For this reason, even if the mask image is combined with the original image and the stamp image is combined with the mask image area in the original image, no color bleeding or whitening occurs on the periphery of the stamp image.

1 is a block diagram showing an image forming apparatus to which an embodiment of an image processing apparatus of the present invention is applied. It is a figure which illustrates the image component of CMYK which comprises a stamp image, a mask image, and a stamp image. FIG. 4 is a diagram illustrating a document image, a CMYK image component constituting the document image, a CMYK image component combined with a mask image, a CMYK image component combined with a stamp image, and a document image combined with a stamp image. It is a calculation table | surface which shows the AND composition of the image component of CMYK, and a mask image. It is a block diagram which shows the conventional image forming apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an image forming apparatus to which an embodiment of an image processing apparatus of the present invention is applied. In this image forming apparatus 1, image data of a manuscript image or a stamp image is input from an external personal computer 2 in the form of PDL (page description language) data, or a manuscript image is read to obtain RGB data (image data) of the manuscript image. ) And irreversible compression processing (for example, JPEG compression processing) of RGB data of a document image or stamp image, and storing those JPEG data in a memory or generating image data of a mask image based on the stamp image To store in memory. Also, JPEG data of a document image or stamp image is read from a memory and decompressed to obtain RGB data, RGB data of the document image or stamp image is converted into CMYK data (image data), and an image of a mask image The data is read from the memory, the mask image is combined with the document image, the stamp image is combined with the mask image in the document image, and the document image combined with the stamp image is printed.

  Such an image forming apparatus 1 includes a PDL data processing unit 11 that analyzes a document image or a stamp image input in the PDL data format, a scanner 12 that reads the document image and outputs RGB data of the document image, and a document JPEG compression processing unit 13 for irreversible compression processing of RGB data of images and stamp images, mask image generation unit 14 for processing RGB data of stamp images to generate image data of mask images, and image data of mask images JBIG compression processing unit 15 that performs reversible compression processing, HDD 16 that stores JPEG data (image data) of a document image or stamp image and JBIG data (image data) of a mask image, and decompression processing of JPEG data of a document image or stamp image After converting to CMYK data or decompressing the JBIG data of the mask image The image forming apparatus includes a combining unit 17 that combines the mask image with the document image, combines the stamp image with the mask image (white area) in the document image, and a printing unit 18 that prints the document image combined with the stamp image. Yes.

  The PDL data processing unit 11 analyzes the RGB data of the document image and the stamp image input from the external personal computer 2 in the PDL data format, extracts the RGB data of the document image and the stamp image, and extracts the document image and the stamp image. RGB data is output to the JPEG compression processing unit 13, and the RGB data of the stamp image is output to the mask image generation unit 14.

The scanner 12 reads an original image and outputs RGB data of the original image to the JPEG compression processing unit 13. When the JPEG compression processing unit 13 inputs RGB data of the original image or stamp image, the RGB of the original image or stamp image is input. The data is subjected to irreversible compression processing (JPEG compression processing) to generate JPEG data of a document image or stamp image, and the JPEG data of the document image or stamp image is stored in the HDD 14.

  Further, when the RGB image data of the stamp image is input, the mask image generation unit 14 determines whether or not each pixel of the stamp image is a colored pixel based on the RGB data of the stamp image. For example, the value of the corresponding pixel in the mask image is set to “0”, and if it is not a colored pixel, the value of the corresponding pixel in the mask image is set to “1” and the mask image (binary image) having the same pixel matrix as the stamp image Is generated.

  For example, for each pixel of the stamp image, 8 bits (0 to 255) indicating 256 gradations of R, 8 bits (0 to 255) indicating 256 gradations of G, and 8 bits (0 to 0) indicating 256 gradations of B, respectively. 255), assuming that a total of 24 bits are allocated, a threshold value for tone of R (255-α), a threshold value for tone of G (255-β), and a threshold value for tone of B (255-γ) are set. To do. Then, for each pixel of the stamp image, when at least one of the R gradation, the G gradation, and the B gradation is equal to or less than the threshold (R gradation ≦ (255−α), G gradation ≦ (255− β), gradation of B ≦ (255−γ)), it is determined that the pixel is a colored pixel, the value of the corresponding pixel in the mask image is set to “0”, and the gradation of R, gradation of G, and gradation of B When both exceed the respective threshold values, it is determined that the pixel is not a colored pixel, and the value of the corresponding pixel in the mask image is set to “1”. Therefore, a colored pixel among the pixels of the stamp image is set to the value “0” in the mask image, and a pixel of white or close to white among the pixels of the stamp image is set to the value “1” in the mask image. The

  FIG. 2 shows a stamp image S indicated by RGB data and a mask image M generated based on the stamp image S. The stamp image S is a color image and is composed of colored pixels and pixels that are white or close to white. The mask image M has the same pixel matrix as that of the stamp image S, and each pixel of the mask image M corresponding to each colored pixel of the stamp image S is set to a value “0”. Each pixel of the mask image M corresponding to each pixel close to white is set to the value “1”, and the mask image M is generated.

  When the mask image generation unit 14 generates image data of such a mask image (binary image), the image data of the mask image is output to the JBIG compression processing unit 15.

  When the image data of the mask image is input, the JBIG compression processing unit 15 performs reversible compression processing (JBIG compression processing) on the image data of the mask image, generates JBIG data of the mask image, and generates the JBIG data of the mask image. Store in the HDD 14.

  Accordingly, the RGB data of the document image and the stamp image is subjected to irreversible compression processing (JPEG compression processing) and stored in the HDD 14 as JPEG data. The image data of the mask image (binary image) is subjected to lossless compression processing (JBIG compression processing) and stored in the HDD 14 as JBIG data.

  Since the RGB data of the original image and the stamp image has a large amount of data, they are highly compressed by irreversible compression processing (JPEG compression processing) to reduce the file size in the HDD 14. The image data of the mask image (binary image) is stored in the HDD 14 after the lossless compression process (JBIG compression process) because the data amount is small and it is necessary to avoid the deterioration of the image quality. .

  Next, a process for synthesizing a document image, a mask image, and a stamp image by the synthesis unit 17 will be described.

  In the combining unit 17, the first JPEG decompression processing unit 21 reads JPEG data of the document image from the HDD 16, decompresses the JPEG data of the document image, and forms RGB data of the document image. The RGB data of the document image is converted into CMYK data by the first image processing unit 22, and the CMYK data of the document image is input to the mask image synthesis unit 23.

  Further, the JBIG decompression processing unit 24 reads the JBIG data of the mask image from the HDD 16 and decompresses the JBIG data of the mask image to form image data of the mask image (binary image). The image data of the mask image is input to the mask image synthesis unit 23.

  When the CMYK data of the original image and the image data of the mask image are input, the mask image synthesizing unit 23 performs a synthesis process of these data, that is, a process of synthesizing the mask image (outline area) with the original image. CMYK data of the original image synthesized with the mask image is formed. The CMYK data is input to the stamp composition unit 25.

  On the other hand, the second JPEG decompression processing unit 26 reads the JPEG data of the stamp image from the HDD 16 and decompresses the JPEG data of the stamp image to form RGB data of the stamp image. The RGB data of the stamp image is converted into CMYK data by the second image processing unit 27, and the CMYK data of the stamp image is input to the stamp combining unit 25.

  When the stamp combining unit 25 receives the CMYK data of the original image combined with the mask image and the CMYK data of the stamp image, the stamp combining unit 25 combines these data, that is, combines the stamp image with the mask image (white area) in the original image. The CMYK data of the original image obtained by combining the stamp images is formed. The CMYK data is input to the printing unit 18. When the printing unit 18 receives the CMYK data of the original image combined with the stamp image, the printing unit 18 prints the original image combined with the stamp image on the recording paper.

  FIG. 2 conceptually shows CMYK data converted from the RGB data of the stamp image S. Here, the CMYK data 31 of the stamp image S indicates a stamp image component SC of C (cyan) color and a stamp image component SM of M (magenta) color. The CMYK data 31 indicating the stamp image components SC and SM is output from the second image processing unit 27 and input to the stamp composition unit 25.

  3 shows the RGB data of the original image Q, the CMYK data 33 converted from the RGB data of the original image Q, the CMYK data 34 of the original image Q synthesized with the mask image M, and the CMYK of the original image Q synthesized with the stamp image S. A document image Q obtained by combining the data 35 and the stamp image S is conceptually shown.

  As shown in FIG. 3, the original image Q (RGB data) is a C (cyan) original image component QC, an M (magenta) original image component QM, a Y (yellow) original image component QY, and a B ( The document image component QB (CMYK data 33) of black) is converted.

  A mask image M is AND-synthesized with the C-color document image component QC, the M-color document image component QM, the Y-color document image component QY, and the B-color document image component QB. The calculation table of this AND composition is shown in the diagram of FIG.

  As described above, in the mask image M, since each pixel corresponding to each colored pixel of the stamp image S is set to the value “0”, the C original image component QC, the M original image In each of the component QM, the Y-color original image component QY, and the B-color original image component QB, each pixel corresponding to each pixel of the mask image M is set to white by AND composition, and the mask image M The overlapping area is outlined. Further, since each pixel of the mask image corresponding to each pixel of white or near white of the stamp image is set to the value “1”, the C document image component QC, the M document image component QM, Y In each of the original document image component QY of color and the original document component QB of color B, the respective colored pixels (C color, M color, Y color) corresponding to the respective pixels of the mask image M are obtained as they are by AND composition. Maintained. As a result, the C document image component QC, the M document image component QM, the Y document image component QY, and the B document image component QB synthesized from the mask image M (outline region), that is, the mask. A document image Q synthesized with the image M is generated (CMYK data 34).

  The stamp image S of FIG. 2 is combined with the white area of the mask image M in the document image Q (CMYK data 35). However, since the stamp image S of FIG. 2 is composed of only the C-color stamp image component SC and the M-color stamp image component SM, the C-color document image component QC is combined with the C-color stamp image component SC, Only the M stamp image component SM is combined with the M document image component QM.

  Further, the C document image component QC, the M document image component QM, the Y document image component QY, and the B document image component QB indicated by the CMYK data 35 are printed over the recording paper, and stamped A document image Q obtained by combining the images S is printed.

  As described above, in this embodiment, a mask image (binary image) is generated based on the stamp image before being subjected to the reversible compression process, and the image data of the mask image is reversibly compressed or stored in the HDD 16 without being compressed. Therefore, the image quality of the mask image does not deteriorate. For this reason, even if the mask image is read from the HDD 16, the mask image is combined with the original image, and the stamp image is combined with the mask image area in the original image, no whitening occurs at the periphery of the stamp image.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. It is understood.

  For example, the composition process of the mask image and the document image may be performed by other arithmetic processes instead of the AND composition. If the number of bits indicating the tone of the pixel in the mask image or the document image is small, AND synthesis may be performed. However, if the number of bits is large, more complicated arithmetic processing is required. Similarly, the combination processing of the stamp image and the document image may be performed by other arithmetic processing instead of OR combination. Further, as the lossy compression process and the lossless compression process, other processes different from the JPEG compression process and the JBIG compression process may be applied.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Personal computer 11 PDL data processing part 12 Scanner 13 JPEG compression process part 14 Mask image generation part 15 JBIG compression process part 16 HDD
17 Composition unit 18 Printing unit

Claims (6)

An image processing device that generates a mask image based on a stamp image, combines the mask image with an original image, and combines the stamp image with an area of the mask image in the original image,
A storage unit for storing the image data of the stamp image and the image data of the mask image;
A mask image generating unit that generates the mask image based on the stamp image before being subjected to compression processing and compresses the image data of the mask image or stores the image data in the storage unit without compression. An image processing apparatus. The image processing apparatus according to claim 1,
The image data of the mask image is read out from the storage unit and processed without being expanded, the mask image is combined with the original image, and the image data of the stamp image is read out from the storage unit, and processed. An image processing apparatus comprising: a combining unit that combines the stamp image with the mask image area in the document image. The image processing apparatus according to claim 1, wherein:
The image processing apparatus, wherein the mask image generation unit compresses image data of the stamp image and stores the compressed image data in the storage unit. The image processing apparatus according to claim 3,
The compositing unit reads out the image data of the mask image from the storage unit and processes the image data without decompression or decompression, composes the mask image with the document image, and stores the image data of the stamp image in the storage unit An image processing apparatus, wherein the stamp image is combined with the area of the mask image in the original image by reading out and decompressing the image. An image processing apparatus according to any one of claims 1 to 4,
The image data of the original image and the image data of the stamp image are RGB data,
The synthesizing unit converts the image data of the document image and the image data of the stamp image from RGB data to CMYK data, and then synthesizes the mask image with the document image, and the area of the mask image in the document image An image processing apparatus, wherein the stamp image is synthesized.   An image forming apparatus comprising the image processing apparatus according to claim 1.

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